1. Field of the Invention
The invention relates to a method of estimating a supporting state of an electronic apparatus housing, and an electronic apparatus.
2. Description of the Related Art
In recent years, portable electronic apparatuses such as notebook personal computers and mobile phones have become widespread. Portable electronic apparatuses are not only used in the state of being placed on a flat surface such as a desktop, but also used in various forms or positions. For example, portable electronic apparatuses are used in the state of being held by hand, or mounted on soft objects such as the user's lap or carpets. Further, portable electronic apparatuses may be operated in various positions, such as special cases of being operated in the bag. As described above, since portable electronic apparatuses are used in various forms or positions, the mechanical supporting state of the housing of the electronic apparatus varies.
The mechanical supporting state of the housing of an electronic apparatus is important information for managing the operating state of the apparatus, in controlling heat radiation and controlling an auxiliary storage device such as a hard disk drive.
First, explained is an example in which heat radiation is controlled according to the mechanical supporting state of the housing. In electronic apparatuses, openings for taking and exhausting air are provided in the bottom portion of the housing, and the housing is generally supported by leg portions when the apparatus is used on a flat surface such as a desktop. As a result, there is a certain space between the desktop and the bottom surface of the housing, and heated exhaust air discharged from the openings is discharged through the space, and thereby heat in the apparatus is radiated. Therefore, the space functions as an air intake and exhaust path for heat radiation. On the other hand, when electronic apparatuses are used on a soft object such as the user's lap and carpet, it is not always ensured that there is a space between the soft object and the bottom surface of the housing, and the heat radiation property of the apparatus differs from that in the case of placing the electronic apparatus on a desktop.
Next, explained is a case where an auxiliary storage device such as a hard disk drive is controlled according to the supporting state of the electronic apparatus. Hard disk drives perform very sophisticated mechatronic control in which a magnetic head accesses a region on a storage disk while the storage disk is rotated at high speed. The mechanical characteristic differs between the case where the electronic apparatus is used on a stable flat surface such as a desktop and the case where the electronic apparatus is used in various positions such as in the bag, and it is necessary to change control of the hard disk drive according to the supporting state of the electronic apparatus.
In prior art, there is a method of estimating the supporting state of the housing by an acceleration sensor mounted on the housing, as a technique of estimating the supporting state of the housing of an electronic apparatus. The position or movement of the electronic apparatus is monitored by an acceleration sensor mounted on the electronic apparatus. JPA No. 2007-200508 (KOKAI) discloses a technique in which a magnetic head is retracted into a safe region outside the disk, when it is determined during the monitoring that an impact may be given to the hard disk drive. Although this prior technique has already gone into actual use, the prior technique only senses dynamic input from the outside of the electronic apparatus, and cannot estimate the supporting state of the housing in a static state. Thus, the prior technique is not always sufficient.
As described above, the method of estimating the supporting state of the housing of an electronic apparatus in prior art has the following problem. When an acceleration sensor is used alone, the acceleration sensor only senses dynamic input from the outside of the electronic apparatus. Therefore, it is impossible to estimate the supporting state of the housing in a static state or in an acceleration/deceleration state which is smaller than the sensitivity of the acceleration sensor, and the electronic apparatus is not always in a sufficient monitoring state. Further, there is no prior art or idea relating to a method of estimating the supporting state of the housing in a static state at practical cost.